| abstract |
A method comprises providing a structure comprising a substrate; a first gate structure and a second gate structure over the substrate; a first source / drain (S / D) feature and a second S / D feature over the substrate; a first dielectric layer over sidewalls of the first and second gate structures and over the first and second S / D features; and a second dielectric layer over the first dielectric layer. The first and second S / D features are adjacent to the first and second gate structures, respectively. The first and second S / D features comprise different materials. The method further comprises etching the first and second dielectric layers to expose the first and second S / D features, doping a p-type dopant into the first and second S / D features, and applying a selective etching process to the first and second S / D features after doping of the p-type dopant. The selective etching process deepens the first S / D feature faster than the second S / D feature. |